3. Finally, obtain the control flow versus power jet deflection 

 characteristics for the experimental element. These charact- 

 eristics were used in designing the location and size of the 

 amplifier's output ports, and in developing a theory for pre- 

 dicting its performance. 



Thus an experimental element was designed and built. Based upon 

 the results of reference 5, the active leg was designed with an aspect 

 ratio (depth/width) of 0.8 and ratio of its radii (inner radius /outer 

 radius) as 0.20 such that the separation in the bend will occur natural- 

 ly. From the momentum balance considerations one can see that the angle 

 between the active and the passive legs of the element can be anjrwhere 

 from to 180 . However, the 90 angle makes the power jet emanating 

 angle very sensitive to the passive leg flow without decreasing its 

 axial momentum appreciably. The dimensions of the active and passive 

 leg flow passages were determined for a designed flow of 2.5 gpm each. 

 The corresponding flow Reynolds number through the supply flow passages 

 was in the range of 13,000. A sketch of the element is shown in Figure 

 3. The control for the element was of counter flow type secondary 

 injection. The control slot was extended the full depth of the channel 

 with a width of 1/16 inches. The location and other pertinent details 

 of the control slot are shown in Figure 4. The details of the power 

 jet separation surface of the element are shown in Figure 5. Further, 

 Table 1 lists the dimensions and important parameters of the designed 

 element. 



Experimental Program 



A test program was designed to determine the suitable design of 

 the element by trial and error procedure. Extensive tests were run 

 to derive the element's characteristics. 



The experiments were conducted in the Mechanical Systems Laboratory 

 at NCEL using regular tap water as the working fluid under carefully 

 controlled flow and pressure conditions. All experiments were performed 

 under continuous flow conditions so that sufficient time was available 

 for stabilization of all flows and instrument readings. The general 

 arrangement of various flow lines and instruments of the test setup 

 are shown in the schematic of Figure 6. The adjustment of the supply 

 flow is possible by the hand controlled valves provided on the line. 

 The control flow to the element was provided by means of a pumping 

 system capable of creating positive pressure in the line. The element 

 remained immersed in water throughout the test series. 



Supply and control flows were measured by rotameters. Static 

 pressures were measured by the conventional pressure gages. Throughout 

 the test program, a dye injection technique was used for flow visuali- 

 zation through the element. This method consisted of injecting a 

 concentrated solution of methyl blue (a blue dye) through the ports 



